Recently, storage media have been widely developed while the consumer electronics products have become popular. The storage capacities of the storage media keep increasing and the sizes of the storage media keep minimizing. People prefer to use storage media to store audio file, video file, text file, or image file to share with others or to use by themselves. Such digital files in storage media are easily deleted or formatted by the user unconsciously, and may be copied by others who get the storage media unauthorizedly. Therefore, a content protection system has been developed in recent years. A conventional content protection system usually can protect the file stored in a storage medium from being deleted unconsciously.
For example, in a conventional USB storage device, the storage area is divided into an area in which execution of reading, writing and deleting is allowed and an area in which only execution of reading is allowed. Information to make a USB mass storage class driver recognize these areas as areas corresponding, respectively, to logical unit numbers defined in the SCSI command set of the USB mass storage class driver owned by the host is stored in the USB storage device. The information includes logical unit numbers, formats, writing/deleting allowed/not allowed flag, logical block numbers and physical block numbers. By this, the USB mass storage class driver recognizes the USB storage device as a SCSI device having two logical units.
The conventional USB storage device as aforementioned can prevent files in a read-only area from being deleted. However, such USB storage device cannot prevent files from being hacked or mass copied by a hacker or an illegal user unauthorizedly because the two logical units in the conventional USB storage device are still visual. Therefore, there is still a demand for providing a content protection system which can protect files in storage media from being hacked or mass copied.